Process for polymerizing olefins and polymerization catalyst therefor

Abstract

An olefin polymerization catalyst formed from (A) a solid titanium catalyst component containing magnesium, titanium and halogen as essential ingredients, (B) an organoaluminum compound, and (C) an organosilicon compound containing a cyclopentyl group, a cyclopentenyl group, a cyclopentadienyl group or a derivative derived from any of these groups. A polymerization process which comprises polymerizing or copolymerizing olefins in the presence of the olefin polymerization catalyst to form a homopolyolefin having a high stereoregularity or a copolyolefin having a narrow composition distribution.

We claim: 
     
       1. An olefin polymerization catalyst formed from (A) a solid titanium component which contains magnesium, titanium, halogen and an electron donor as the essential components prepared by contacting of a magnesium compound with a titanium compound and an electron donor, said magnesium compound having been for a time in a liquid condition during preparation of said solid titanium component;   (B) an organoaluminum compound; and   (C) an organosilicon compound represented by the following formula   SiR.sup.21 R.sup.22.sub.m (OR.sup.23).sub.3-m        wherein R 21  represents a cyclopentyl group, a cyclopentyl group substituted by 1 to 4 alkyl groups having 1 to 4 carbon atoms, an alkyl group having 2 to 4 carbon atoms substituted by a cyclopentyl group or a cyclopentyl group substituted by 1 to 4 alkyl groups having 1 to 4 carbon atoms, a cyclopentenyl group, a cyclopentenyl group substituted by 1 to 4 alkyl groups having 1 to 4 carbon atoms, a cyclopentadienyl group, a cyclopentadienyl group substituted by 1 to 4 alkyl groups having 1 to 4 atoms, an indenyl group, an indenyl group substituted by 1 to 4 alkyl groups having 1 to 4 carbon atoms, an indanyl group, an indanyl group substituted by 1 to 4 alkyl groups having 1 to 4 carbon atoms, a tetrahydroindenyl group, a tetrahydroindenyl group substituted by 1 to 4 alkyl groups having 1 to 4 carbon atoms, a fluorenyl group or a fluorenyl group substituted by 1 to 4 alkyl groups having 1 to 4 carbon atoms;   R 22  and R 23  are identical or different and each represents a hydrocarbon group; and   0≦m<3.   
     
     
       2. The catalyst of claim 1 in which the solid titanium catalyst component (A) is obtained by using a titanium compound of the following formula   Ti(OR).sub.g X.sub.4-g     wherein R represents a hydrocarbon group, X represents a halogen atom and g is a number of 0 to 4.   
     
     
       3. The catalyst of claim 1 in which the organoaluminum compound (B) is an organoaluminum compound having at least one aluminum-carbon bond in the molecule.